Device for detecting the raising state of small piles of dough

ABSTRACT

The present invention relates to a device for detecting the raising state of lumps of dough ( 11 ) submitted to a fermentation process which is for example induced by yeast in a raising chamber and during which the volume of said lumps increases. The device includes at least one variance detector ( 21 ) which is associated with at least one of the lumps of dough placed in the raising chamber, and which generates a characteristic output signal when the thickness of the dough reaches a predetermined target value corresponding to a desired maturation degree of the dough. The variance detector ( 21 ) consists of an ultrasonic detector for measuring the propagation time of the ultrasonic signals. The detector is placed on a tripod ( 17 ) which can be arranged in the raised chamber ( 13 ) on the bottom thereof.

BACKGROUND TO THE INVENTION

1. Field of the Invention

The invention concerns a device for detecting the state of rising oflumps of dough which are subjected to a proofing or fermenting processin a proofing chamber, for example induced by yeast, in the course ofwhich the lumps of dough experience an increase in volume.

2. Description of the Related Art

The typical bakery products such as bread or rolls, which are sold dailyin large quantities by branches or retail outlets of bakery factories,in order to be able to represent that they conform to the highestpossible levels of freshness and quality, are baked in the respectivebranch or outlet locations, whereby it is also achieved that theproduced amount can be flexibly adapted to the respective demand.Herein, for example, in the production of table rolls, the processbegins with lumps of dough, which are pre-produced in a roll producingequipment in large number with substantially identical weight andvolume. These lumps of dough, which are already subjected to yeast intheir manufacture, are, prior to the rolls can be baked in an oven,subjected to a rising step in a proofing chamber, in which the size anddough consistency required for the baking of the rolls is strived for.Herein the proofing process is so carried out, with respect to thechamber temperature and in certain cases the dwell time, that during atotal proofing time of approximately 20 minutes the necessary dough sizeis achieved, which in typical cases represents the five fold of thevolume of the fresh “green” dough lumps produced on the roll producingdevice before the initiation of the rapidly occurring proofing processis set in motion therein by the elevation of the temperature, after thecourse of which, that is as soon as the dough lumps have achieved theirdesired size, these should be baked immediately, in order to achievetable rolls of standardized desired quality. The most importantcharacteristic of quality of the finished baked rolls, which isassociated in the mind of consumer with the image of quality, is thesize thereof, which should also be uniform among the various types ofrolls.

In order to achieve this uniformity, it would seem to be basicallysuitable to employ constant uniform conditions for carrying out theproofing process, for example using a computer program controlledtime-wise control of the proofing chamber temperature, combined with anindication that the proofing time has concluded as determined by thetemperature profile. Through such a temperature control it is howevernot possible to exclude influences on the size of the proofed doughlumps, which result from variations in yeast quality and/or variationsin the introduction temperatures of the “green” dough lumps, and whichcan lead to significant size variations of the proofed dough lumps. Itis thus necessary, even when employing a uniform time controlledproofing of the dough lumps, to subject the dough lumps treated in theproofing chamber to a visual quality control before they can beintroduced into the baking oven, which however demands a high level ofpractical experience, in particular in that respect of how in certaincases a proofing process is to be carried out up to suitable ripeness ofthe dough lumps. The sales persons employed in the branches, which mayhave only limited knowledge of the baking process, do not as a rule havethis particular necessary experience. This has the consequence thatoften it is only after the table rolls have been baked that it can berecognized whether these satisfy the required quality characteristics.

SUMMARY OF THE INVENTION

It is thus the task of the invention to provide a device of the abovedescribed type, which makes possible a reliable, objective measurementof the respective proofing condition of the dough lumps, whichcorrelates to their desired final size.

This task is inventively solved thereby, that a distance sensoroperating on a contactless measurement principle is provided inassociation with at least one of the dough lumps provided in theproofing chamber, which at least then, when the thickness of the doughlump achieves a predetermined desired value, which is associated withthe intended condition of proofing of the dough lump, produces a signalwhich is characteristic therefore.

The inventive device is based on the fact that the volume increase,which the dough lump experiences through the proofing process, seen fromits center of gravity, leads to a dimensional enlargement in everydirection, so that by measurement of the distance or separation of asurface point or area of the dough lump from the position at which thesensor is situated, a very reliable determination of the volume of thedough lump, or its proofing ripeness condition, is made possible.Starting with an absolute measurement of the starting distance asreference value, and with the progressive measurement of the reductionof this separation, the volume of the dough lump is determinable withsufficient precision, so that from such a distance measurement asufficiently precise indication with respect to the ripeness of thedough lump can be determined.

By means of the invention the objective determination of the conditionof ripeness of the monitored dough lump is made possible in a simplemanner, and therewith also that of other dough lumps identical to thisdough lump. The inventive device makes possible at the same time anautomatic monitoring of the proofing process and in certain cases alsopermits, depending upon the instantaneously detected volume of the doughlumps, to control the proofing process by influencing the proofingchamber temperature in such a manner, so that the condition of ripenessnecessary for the subsequent baking process of the dough lumps isachieved after the expiration of a pre-determined time span. Theinventive device is suitable for avoiding inaccurate determinations ofthe condition of ripeness of the dough lumps and therewith makespossible the rational production of baked wares in a branch or chainoperation.

In a preferred design of the inventive device the distance sensorthereof is arranged and oriented in such a manner that it measures theheight of the dough lump, in the central area thereof, over the sheet orsupport, which is useful as a measuring value for the reason that it isdeterminable in relation to a fixed pre-determined reference value,namely the distance of the support for the dough lumps to the distancesensor, which is pre-determined by the construction specifications ofthe proofing chamber. Further, the vertical thickness of a dough lumpduring the proofing process, even in the case that this is smaller thanthe largest horizontal cross-section, will change a greater amount thanmeasurable by a “horizontal” distance measurement of the horizontalradius of the dough lump, since the vertical thickness change iscomprised of the sum of the distance change from the center point of thedough lump to the support plus the change in the vertical separationfrom the dough lump upper surface to the center point of the dough lump.

A suitable distance sensor to be realized for the inventive device couldfor example be in the manner of a distance measuring and adjustingsystem of an auto-focus camera, or an optoelectronic distance measuringdevice, which however because of the required optical imaging of thetarget or measurement object is associated with a substantial spacerequirement, which would be acceptable only in the case of a fixedinstallation in a chamber with high capacity.

In a preferred design of the inventive device the distance sensor isthus designed as an ultrasonic sensor, which works on the principle ofthe elapsed travel time measurement of the ultrasonic signal. A distancesensor of this type only requires a small amount of space and can beinstalled without complication between two support surfaces for doughlumps within a proofing chamber, so that sufficient space for themonitored dough lump still remains below the sensor.

In accordance therewith the distance sensor can be provided on aframework which can be set up on the floor inside a conventionalproofing chamber, preferably a three legged framework, and insofar issuitable as a retrofit component for existing proofing cabinets.

As distance sensor a light interruption device is also suitable, inwhich a light beam is interrupted as soon as at least one of the doughlumps achieves a height that is characteristic for a desired degree ofripeness.

A light interruption device is preferably fixedly installed in theproofing cabinet, wherein the light source and the light detector can bebuilt into the proofing cabinet walls preferably in such a manner, thatthe light detector is height adjustable, wherein the heightadjustability can be realized in simple manner thereby, that the lightsource is height adjustable and a receiver line is provided fixed in thechamber, comprised of a number of light detectors arranged in smallvertical separation from each other, or a single receiver with receiversurface extending in the vertical direction, as well as a gate oraperture which is adjustable in height to a pre-determined distanceabove the floor which carries the dough lumps.

In a preferred design of such a light detector the detector light beamis so arranged that it crosses over multiple dough lumps, for example acentrally oriented row of dough lumps, whereby even in the case of aminor irregular arrangement of the dough lumps the probability isincreased that the light detector is interrupted at the correct point intime, even when the light detector-light beam does not precisely crossover the central plane of some of the individual dough lumps.

In one embodiment of the distance measuring device as a light detectordevice, it is particularly advantageous when a laser is employed as alight source, which emits a strongly bundled parallel light beam ofsmall cross-section and high light intensity without requirement forspecialized optical elements and/or apertures, which in an advantageousembodiment of the invention can be divided by means of a simple beamsplitter into multiple partial light beams of preferably approximatelythe same intensity, which can be utilized for monitoring of dough lumpsin multiple planes of a proofing chamber or even for monitoring of doughlumps in multiple proofing chambers, which are positioned in spatiallyfixed coordinates within a larger proofing facility, in which theemployment of a laser can be more economical than an arrangement oflight detectors which have respectively one individual light source ofsimple design.

The reliability of recognition of the interruption of a lightinterruption device in accordance with a further embodiment of theinvention is thereby improved, in that at least one scatter-lightdetector is provided, preferably in a device above the sensor planedefined by the light interruption device, wherein the scatter-lightdetector produces a signal, when the light shutter interrupting areas ofa dough lump are illuminated by the light interruption device light beamand thereby scatter light, which is easy to construct by means of asimple imaging system uniformly monitoring the dough lumps, and which byusing a light detector can be utilized for producing a confirmationsignal.

BRIEF DESCRIPTION OF THE DRAWING

Further details of the inventive device can be found in the followingdescription of exemplary embodiments thereof as illustrated by thedrawings. There is shown:

FIG. 1 a schematic simplified step diagram of a proofing cabinet, whichis outfitted with an inventive distance measuring device;

FIG. 2a and 2 b a suitable ultrasonic type distance sensor for use in aproofing chamber according to FIG. 1;

FIG. 3 a schematic simplified representation of the light interruptiondevice, which can be used as measuring device in the proofing chamberaccording to FIG. 1;

FIG. 4 a schematic representation of a beam splitter device, by means ofwhich the output light beam of a laser can be distributed to pluralityof light interruption devices.

DETAILED DESCRIPTION OF THE INVENTION

In the proofing chambers indicated overall with reference number 10 inFIG. 1 there are dough lumps 11, for example for table rolls, which canbe subjected to a proofing process, before they can be finally baked ina baking oven (not shown) immediately after completion of the proofingprocess.

By means of this proofing process the dough lumps 11, which undergo asubstantial increase in volume during the proofing process, are to bebrought to the suitable consistency of the dough for baking, whichbrings about once again further volume increase up to the final size ofthe finished rolls.

Herein the dough lumps 11 rest on proofing sheets 12, which are easilyslideable in the sideways guide rails 14, which facilitates the easyintroduction of the dough lumps into the proofing chamber 13 of theproofing cabinet and the removal thereof. These proofing sheets 12 whichhave an approximately square carrying surface 16 are providedrespectively in the same spatial separation h from each other, which forthe purposes of explanation will be presumed herein to be approximately70 mm, wherein it is presumed that the intended thickness d_(s) of thedough lumps 11 as a result of the proofing process, is to have avertical final thickness of approximately 50 mm. In the design presumedfor the proofing cabinet 10 used in this explanation, 6 proofing sheets12 are provided, on which batches of respectively 25 dough lumps 11 canbe deposited.

The proofing cabinet 10 is provided with a hot air convection heatingdevice (not shown), by means of which the temperature produced in theproofing chamber 13 is adjustable and can be changed or varied toconform to a product-optimal temperature curve, over which the proofingprocess is controllable, wherein various temperature curves can bepre-selected and be run by control programs.

For monitoring the proofing process, which results in an increase involume of the dough lumps, a distance sensor indicated overall with 21is provided, by means of which the vertical thickness d in the centralarea of a selected dough lump 11 is determinable, which is monitored ascriteria for the degree of ripeness of the dough lumps 11 subjected tothe proofing process. As soon as the dough lump has achieved thepre-determined intended thickness d_(s), the distance sensor 21 producesan electrical output signal characteristic therefore, which serves as anindicator signal signifying that the dough lumps have achieved theircondition of readiness for baking and, on the other hand, as controlsignal for reducing the temperature in the proofing chamber 13, in orderto stop the proofing process.

This distance sensor 21, now explained in greater detail by reference toFIG. 2a and 2 b, is in constructed the represented special exemplaryembodiment as an ultrasonic sensor, which is mounted on a carryingframework 17 in the manner of a three legged round table in the centralarea of the “table top” 18. The ultrasonic sensor includes an ultrasonictransmitter 22 seated in a flat cell 19, which is seated in a centralborehole of the table top 18, and an immediately adjacent ultrasonicreceiver 23, wherein the ultrasonic sensor 22 is so constructed andarranged, that the central axis 24 of its lobe-shaped emission fieldindicated with dashed lines in FIG. 2b is directed vertically downwards,when the distance sensor 21 with its three leg design 17 is seated uponthe proofing sheet 12 carrying the dough lump 11 to be monitored. Thereceiver 23 is so designed and positioned, that it can receive “direct”ultrasonic transmission emitted slightly sideways from the emitter andreflected from the dough lump 11, so that a measurement of the distanceof a central area of the upper surface of the dough lump 11 from theultrasonic emitter 22, and therewith the known separation of theultrasonic sender 22 from the carrying surface 16 of its framework 17,and also the thickness of the dough lump 11, can be determined in thefollowing manner:

If the emitter 22 is caused to emit ultrasound, then there occursimmediately thereafter in response to the direct emission received“along the shortest path”, which is radiated out sideways, a startingsignal of the receiver 23, which initiates the activation of a timingpulse counter (not shown), which counts the number of counting pulsesproduced for example with the frequency of 1 MHz, until the ultrasonicradiation reflected following reception by the measuring object, thedough lump 11, produces in the receiver a higher level then the startingsignal, the occurrence of which terminates the timing pulse counting.The count of the time counter is then a very precise measurementrepresenting the travel time of the ultrasonic radiation from emitter 22to dough lump 11 and from this to the receiver 23, and can be convertedby a measurement operation driving, essentially schematically indicated,electronic control unit 26 into the thickness d of the dough lump. Inthis mode of operation of the distance sensor 21, which can becalibrated in simple manner by making a reference measurement without adough lump 11, that is, measurement of the distance from the sensor 21to the proofing sheet 16, the measurement of the thickness of the doughlump with a precision of 0.3 to 0.5 mm is easily achieved, which issufficient for monitoring the thickness of the dough lumps. By means ofa time-wise repetition of such a measuring cycle, for example in timeintervals of 10 to 20 seconds, a quasi continuous monitoring of theproofing process is possible, so that based on the value of thecontinuously determined values of the thickness of the dough lump 11 theprocess control can be influenced—“corrected”—by means of the electroniccontrol unit 26 in such a manner, for example by temperature changes inthe proofing chamber 13, so that the proofing process after theexpiration of the defined process time results in the desired degree ofripeness overall of the dough lumps 11.

As already mentioned, the distance sensor 21 which can be introducedinto the proofing cabinet 10 is suitable in particular for aretrofitting of existing proofing cabinets, for which it is essentiallyonly necessary to provide electrical lines for the supply of electricityfor the distance sensor and for relaying signals to the electroniccontrol unit 26. It is also understood that a distance sensor 21 of theabove mentioned type can be permanently installed as a measuring deviceas original equipment in a proofing cabinet 10.

In an alternative design to the ultrasonic sensor, which is suitable inparticular for a permanent installation in a proofing cabinet 10, thedistance sensor is a light interruption device 21′ indicated essentiallyschematically in FIG. 1, for the explanation of the details of whichreference can be made to the discussion of FIGS. 3 and 4.

In the light detector device 21 a laser 29 is provided as light source,for example on the outside of the two parallel vertical cabinet walls,which produces a tightly bundled parallel light beam of small crosssection and relative high light intensity, represented essentially by acentral beam 31, which is emitted in the vertical direction out of thelaser 29. This light beam 31 is redirected about 90° by means of adeflection mirror 32 in order to produce the cabinet light beam 31′necessary for the light detector device and channeled into the proofingchamber 13 via a window 33 provided in the cabinet wall, as shown in therepresentation according to FIG. 3 in the left cabinet wall 27, so thatit passes over multiple dough lumps 11, which are provided on theproofing sheet 12, in defined separation therefrom and impinges ondetector device 34 positioned on the opposite cabinet wall 28,essentially schematically indicated, which produces an output signal ofdefined level, as long as the cabinet light beam 31′ is not interrupted.

In order to be able to adjust the vertical separation of the cabinetlight beam 31′ from the support surface 16 of the proofing sheet, whichcarries the dough lumps 11 being monitored, and thereby to be able toselect the size to which these dough lumps 11 should be allowed to berise, the deflection mirror 32 via which the cabinet light beam 31′ ischanneled into the proofing chamber 13, is designed to beheight-adjustable by means of a schematically indicated rack and piniondrive 36. In accordance therewith the entry window 33 for the cabinetlight beam 31′ is preferably formed to have a narrow slit shape, so thatit extends over the possible adjustment range of the deflection mirrorand herein the detector device 34 is adapted thereto in such a mannerthat its light sensitive receiver surface 37 likewise extends over thepossible adjustment range of the cabinet light beam 31′.

In order to be able to utilize a laser 29, which is capable of producinga relatively high light output, as light source for a multiplicity ofdough lumps 11 when monitoring the proofing process of dough lumps 11,which in certain cases can be provided in various proofing cabinetswhich are positioned with fixed 30 spatial correlation to each otherwithin a larger facility, the beam splitter device shown overall withreference number 38 in FIG. 4 can be used, by means of which the primaryoutput light beam 31 of the laser 29 can be divided into four chamberlight beams of approximately the same intensity, which via a heightadjustable deflection mirror 32 can be channeled into the respectiveproofing cabinets.

The primary output light beam 31 produced by the laser 29 impinges on afirst half-silvered or partially transmissive mirror serving as a beamsplitter 41 and is divided thereby into an—according to therepresentation in FIG. 4—right angled redirected reflected partial lightbeam 42 and a transmitted partial light beam 43, wherein these two lightbeams 42 and 43 have the same intensity. The partial light beam 42reflected by the first beam splitter 41 impinges on a second beamsplitter 44 designed as partially transmissive deflection mirror and isdivided thereby into a transmitted partial light beam 46 and a reflectedpartial light beam 47, which again have the same intensity. The partiallight beam 43 which passes through the first beam splitter 41 impingesupon a third beam splitter 45 designed as partially transmissivedeflection mirror and is there divided into a transmitted partial lightbeam 48 and a reflected partial light beam 49 of respectively the sameintensity.

The four partial light beams 46 through 49 of same intensity can be usedfor forming light interruption detector devices 21 in the manner shownin FIG. 3 in four different proofing chambers.

For the laser 29 in the “vertical” arrangement thereof as shown in FIG.3, that is the vertical emission direction of its primary light beam 31,the emitted light beam 48 and the thereto parallel emitted light beam 47traveling in the direction of the optical axis of the laser 29 can, byemployment of respectively one height adjustable mirror 32, be useddirectly for formation of a height adjustable light detector device 21(FIG. 2). For the two other output light beams 46 and 49 there isrequired, for the indicated purpose, also respectively one 90°deflection mirror 51 or as the case may be 52.

A useful arrangement of the light interruption detection device can alsobe comprised therein, that a scatter light sensor 52 is provided shownessentially in schematic manner in FIG. 1, which is provided above thefirst dough lump, upon which the chamber light beam of the respectivelight detectors can impinge, and, as soon as this dough lump reaches thelight beam, part of this scatter light reaches the detector and therebyis caused to produce an electrical indicator signal.

What is claimed is:
 1. A device for detecting the proofing condition oflumps of dough (11) during a proofing process in a proofing chamber(13), in the course of which the lumps of dough experience an increasein volume, comprising: a proofing chamber (13) including at lest onesurface (16) for receiving lumps of dough; a distance sensor (21)provided in the proofing chamber (13) and positioned for monitoring alump of dough (11); means associated with said distance sensor forproducing an output signal when said distance sensor determines that alump of dough (11) has achieved a predetermined intended thicknessvalue, which is correlated with a desired degree of ripeness of the lumpof dough.
 2. A device according to claim 1, wherein the distance sensor(21) detects the height d of the lump of dough (11) above said surface(16).
 3. A device according to claim 2, wherein said distance sensor(21) is an ultrasonic sensor, which operates based on the principle ofthe travel time of a sound signal.
 4. A device according to claim 1,wherein the proofing chamber includes at least one proofing sheet (12),and wherein the distance sensor (21) is provided on a framework (17)employable in the proofing chamber (13), and adapted for being placed ona surface (16) of the proofing sheet (12) when in the chamber (13).
 5. Adevice according to claim 4, wherein said framework (17) is athree-legged framework.
 6. A device according to claim 1, wherein saidat least one lump of dough has a central area, and wherein the distancesensor (21′) is a light interruption detector for detecting interruptionof a light beam (31′) passing above the central area of at least onelump of dough (11) in the proofing chamber (13).
 7. A device accordingto claim 6, wherein the height of the light beam (31′) in the proofingchamber (13) above the surface (12) carrying the one or more respectivelumps of dough (11) to be monitored is adjustable.
 8. A device accordingto claim 6, wherein the light interruption detector is arranged in theproofing chamber so that the light beam (31′) is able to cross over amultiplicity of lumps of dough (11).
 9. A device according to claim 6,wherein said light beam is a laser beam (29).
 10. A device according toclaim 9, wherein a beam splitter device (38) is provided, which dividesthe output light beam of the laser (28) into multiple partial lightbeams (46, 47, 48, 49), which can be utilized for monitoring theproofing condition of the lumps of dough (11), which are subjected tothe proofing process provided on different surfaces of a proofingchamber or in different proofing chambers.
 11. A device according toclaim 10, wherein at least one scatter light detector (53) is providedfor detecting scatter light.
 12. A device according to claim 11, whereinsaid scatter light detector (53) is positioned above a sensing planedefined by the light beam.